Photoionization-cross-section studies of atomic and final-state effects on the Pb5dcore levels using synchrotron radiation

Using monochromatized synchrotron radiation as the light source, the $\mathrm{P}\mathrm{d}-5d$ cross sections in Pb metal and the $5d_{\frac{5}{2}}:5\mathrm{}{d}_{\frac{3}{2}}$ branching ratios in Pb metal, PbS, PbSe, and Pb${\mathrm{Cl}}_2$ have been studied from 22- to 90-eV photon energies. Constant-initial-state (CIS) spectra for Pb metal from 22 to 40 eV photon energies allow a direct comparison of the $5d_{\frac{5}{2}}$ and $5d_{\frac{3}{2}}$ cross sections. Superimposed on a smooth curve due to atomiclike behavior, the $d_{\frac{5}{2}}$ and $d_{\frac{3}{2}}$ CIS curves show differing structure that is probably related to transitions from the $d$ levels to $p$-like states in the conduction band. The area ratios are chemically sensitive, and at higher photon energies contain structure which is probably due to scattering from neighboring atoms as seen in extended x-ray absorption fine structure.